Persistent storage (such as found in a hard disk, flash memory, or a magnetic tape) may be implemented using block storage. In block storage, the storage space is divided into blocks—portions of the storage space that are a set number of bytes long (the block size). When an operating system attempts to read to or write from a storage device using block storage, the operating system may identify the blocks to be read to or written from by specifying a starting point (such as by specifying a distance from the logical beginning of the disk) and a length of data to be read or written (e.g., 16k bytes).